This disclosure relates to an overload brake for trolley designed to prevent the displacement of suspended trolleys along girders when suspending loads over the maximum capacity range.
Trolleys are typically components of overhead cranes such as bridge and gantry cranes, monorails, tracks, conveyor systems, load column lifters, crane runways, fixed or mobile, whether in linear form straight or curved shaped.
Lifting and handling equipment are typically named bridge cranes, overhead traveling cranes, gantry cranes, runways, monorails or tracks and usually include, in addition support structures and horizontal traveling mechanisms, lifting mechanisms usually called chain, wire rope, manual or electric driven hoists intended for load lifting.
For safe handling, some hoists include mechanical or electrical devices able to prevent overload lifting operations. Whereas if the load limit detection security mechanism is not available, or inoperable, nothing prevents the operator from lifting and displacing a load weighing more than the lifting and handling apparatus design load limit and in this case, the operator becomes responsible to ensure the payload does not exceed the maximum allowable load for the lifting and moving device.
The load limit detection devices are typically mounted directly on the component that suspends the load or indirectly via torque detection through clutches for torque arms. The load limit detection device blocks the lifting operation when overloads are detected.
There are also mechanical devices that limit the translation of the suspended load independent of the load lifting limitation devices. These devices require additional mechanisms of elastic deformation exclusively dedicated load detection and acting on the locking elements or locking of the translatory movement of the cars that support the loads figures.